玉米幼苗莖葉及根系性狀之全互交分析

Abstract

六個玉米自交系親本及其三十個單交組合，於1991年秋作進行溫室試驗，資料利用Griffing方法3作固定模式全互交分析。試驗结果，6〜7葉齡的玉米幼苗，雜交種比自交系具有較大的苗高、葉片數、主根數、根鮮重、地上部鮮重、根體積、植株總乾重及根系比例。幼苗莖葉及根系性狀的一般組合力(General combining ability，GCA)及特定組合力(Specific combining ability. SCA)均方均達極顯著。所調查之性狀的GCA/SCA比值大於1，顯示累加性基因之作用較大於非累加性基因之作用。主根數及根體積具有正反交效應存在。玉米幼苗莖葉及根系之性狀有明顯的雜種優勢，主根數為11.46%〜41.43%、根鮮重為42.8%〜224.8%、根體積為25.9%〜176.1%、根系比例為-0.62%〜36.16%。幼苗莖葉性狀及根系性狀間之相關均極顯著，由於葉片數與主根數、根鮮重、根體積、根系比例均為極顯著正相關，利用葉片數作為改良幼苗根系之選拔指標，或為可行之方法。 Six inbred lines and their thirty single cross hybrids were evaluated for seedling shoot and root system characteristics in greenhouse studies conducted in fall of 1991. Results of Griffing's method 3 model I diallel analysis indicated that both general (GCA) and specific (SCA> combining ability were highly significant for all characteristics Additive effects accounted for major part of the total variation Reciprocal effects (RE) were found in primary root number and root volume. Heterosis ranged from 11 -46% for primary root number to 224.84% for fresh root weight. Highly significant positive correlations were observed between leaf number and root system characteristics. This result indicated that leaf number could be a useful selection index for improving seedling root system.